Viruses have been the major life threatening microorganisms since time immemorial. All viruses are infective unlike all bacteria that can also be beneficial. Viruses are known to cause various types of cancers also such as Hodgkin’s, non-Hodgkin’s lymphomas, cancers of the throat and liver. Viruses basically cause cancer by mutating a critical gene for replication in the host DNA leading to an uncontrolled cell division.

A team of scientists led by Preet M. Choudhary, M.D., Ph.D., and professor of medicine at University of Pittsburgh have proposed that viruses in a way, act as elements of natural selection.

The theory of natural selection put-forth by Charles Darwin can simply be stated as, fixation of a desirable mutation of a gene. Similarly, viruses have been found to kill normal cells that favour the replication of viruses, leaving behind the defective cells. Repetition of this process over and over causes cancer.

‘We believe, a separate mechanism may be at play in which a cellular insult, such as infection with the virus, selects a few pre-existing mutated clones of cells promotes their further growth and multiplication, eventually leading to the emergence of fully cancerous cells, consequently, similar to the role played by natural selection during evolution, excessive cell death, rather than its absence may be the defining force that drives the initial emergence of cancer,’ said Dr. Choudhary.

Since, notably the cancerous condition arises from the ‘ashes’ of dead cells, Dr.Choudhary calls it ‘Phoenix Paradigm‘. A study was conducted wherein, cells were infected with Kaposi’s sarcoma associated Herpes Simplex Virus (KSHV) also called Human Herpes Simplex Virus-8 (HHV-8) and examined the K13 cell-signaling pathway. They observed that cells with low K13 levels, favoured KSHV replication and subsequently died, but up regulating K13 gene expression in the existing cells and down regulating two key proteins involved in promoting cancer.

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via : CBCnews

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